Papers by Author: Hong He Ma

Abstract: A simulation model was developed for predicting the particle size evolution in hydrothermal synthesis of nanoparticles in supercritical water. Four elementary kinetic processes, including hydrothermal synthesis reaction, nucleation, growth, and aggregation, were involved based on the population balance equations (PBEs). The homogenous nucleation of metal oxide nanoparticles started at the operation time of 3.72μs. When the rate constant of hydrothermal synthesis reaction lnk increased from 2.8 to 6.16, the nucleation rate increased by three orders of magnitude (1021-1024particles/m3•s) and the nucleation period reduced from 0.2s to less than 0.02s. The APS decreased by approximately half when a ten-fold smaller growth rate constant was adopted in the range of 10-11-10-8.

Abstract: A supercritical water oxidation (SCWO) reactor containing a hydrothermal flame as heat source is simulated by computational fuild dynamics (CFD) simulation. Methanol solution and oxygen are fed separately into the reactor as fuel and oxidizer, and at the same time the cold waste water is also fed into the reactor. The combustion of methanol is simulated by the eddy dissipation concept (EDC) model with an Arrhenius law kinetic. This simulation is conducted to study the behavior of the hydrothermal flame at different inlet fuel temperatures and the relationship between the ignition temperature and methanol mass fraction.